#51ADFF
Closest named color: Deep Sky Blue (#00BFFF). oklch(72.8% 0.148 248.3), rgb(81, 173, 255).
Aa
Black text reads best on this color (8.77:1).
About this color
#51ADFF is a medium-light, vivid blue. In OKLCH its lightness is 73%, its chroma 0.148 and its hue 248°. Its hue sits on the cool side of the wheel. The nearest named color is Deep Sky Blue (#00BFFF), ΔE 0.052 away. Black text reads best on it, at 8.77:1.
| Hue family | Blues |
| Lightness | medium-light (73%) |
| Chroma | vivid (0.148) |
| Temperature | cool |
| Nearest name | Deep Sky Blue (#00BFFF) |
| Black text | 8.77:1 |
| White text | 2.39:1 |
Values
| HEX | #51ADFF |
| RGB | rgb(81, 173, 255) |
| HSL | hsl(208, 100%, 66%) |
| OKLCH | oklch(72.8% 0.148 248.3) |
Contrast
WCAG 2 contrast ratios are the conformance target: AA needs 4.5:1 for body text and 3:1 for large text, AAA needs 7:1. APCA Lc values are supplementary guidance from the WCAG 3 drafts.
| Pair | WCAG 2 | Result | APCA | APCA guidance |
|---|---|---|---|---|
| White text on #51ADFF | 2.39:1 | Fails | Lc -51.8 | Large or bold text, headings |
| Black text on #51ADFF | 8.77:1 | AAA | Lc 57.1 | Large or bold text, headings |
| #51ADFF text on white | 2.39:1 | Fails | Lc 46.9 | Large or bold text, headings |
| #51ADFF text on black | 8.77:1 | AAA | Lc -55.2 | Large or bold text, headings |
Tints and shades
A 50–950 scale built in OKLCH: the hue is held, lightness follows a Tailwind v4-like curve, and every step is kept inside the sRGB gamut. This color sits at step 400.
-
Step 50
50
#EFF6FE
oklch(97% 0.013 251.6)
-
Step 100
100
#DCECFB
oklch(93.6% 0.027 246.3)
-
Step 200
200
#BFDDFA
oklch(88.5% 0.051 247.5)
-
Step 300
300
#91C6FA
oklch(80.9% 0.092 248.6)
-
Step 400
400 (this color)
#51ADFF
oklch(72.8% 0.148 248.3)
-
Step 500
500
#008EEA
oklch(63.2% 0.17 248)
-
Step 600
600
#0077C6
oklch(55.6% 0.15 248.2)
-
Step 700
700
#0064A8
oklch(49.2% 0.133 248.3)
-
Step 800
800
#00528A
oklch(42.8% 0.115 247.8)
-
Step 900
900
#004474
oklch(37.7% 0.101 247.8)
-
Step 950
950
#002848
oklch(27% 0.073 248.1)
#51ADFF with color blindness
Simulated with the Machado et al. (2009) model. ΔE is how far the color moves: below about 0.02 you would not notice a change.
| Vision | Seen as | Shift (ΔE) |
|---|---|---|
| Protanopia (no red cones) | #88B1FF | 0.055 |
| Deuteranopia (no green cones) | #70A0FD | 0.040 |
| Tritanopia (no blue cones) | #00C0CA | 0.111 |
| Achromatopsia (no color) | #A7A7A7 | 0.148 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #51ADFF
#51ADFF
oklch(72.8% 0.148 248.3)
- #E39326
#E39326
oklch(72.8% 0.148 68.2)
Analogous
Neighbouring hues, 30° either side.
Split complementary
The two hues beside the complement (150° and 210°).
Triadic
Three hues spaced 120° apart.
Palettes with this color
Curated palettes that contain a color within ΔE 0.04 (OKLab) of #51ADFF, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Deep Sky Blue #00BFFF ΔE 0.052
- Cornflower Blue #6495ED ΔE 0.063
- Carolina Blue #8AB8FE ΔE 0.065
- Chefchaouen Blue #4895EF ΔE 0.066
- Periwinkle Blue #8F99FB ΔE 0.075
- Bright Sky Blue #02CCFE ΔE 0.085
- Vivid Sky Blue #4CC9F0 ΔE 0.085
- Dodger Blue #1E90FF ΔE 0.088
Use #51ADFF in your product
Turn it into light and dark UI roles checked for contrast, then export to Tailwind v4, shadcn/ui, CSS or design tokens.